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The present invention relates to a vehicular lamp provided with a plurality of LED light sources, and more particularly to a vehicular lamp which radiates light by indirect illumination.
Recently, vehicular lamps provided with an LED light source have frequently been employed. As described in Japanese Patent Application Laid-Open No. 11-306810, a lamp has been developed which provides a soft lighting effect using an indirect illumination technique whereby the LED light source is arranged so as not to be visible from the front of the lamp.
Further, as described in German Patent Application No. 19638081, a lamp structure has been developed in which light from a plurality of LED light sources arranged facing upward is formed into an upward directed parallel light flux by a plurality of Fresnel lenses provided near an upper side of the LED light sources, and the parallel light flux from the Fresnel lenses is then reflected toward the front of the lamp by a reflector. It is possible to effectively utilize the light source light flux by combining the LED light sources and the Fresnel lenses.
However, the vehicular lamp described in German Patent Application No. 19638081 mentioned above is structured such that the reflector extends linearly in a lateral direction. Therefore, in the case where the lamp is mounted at a vehicle body rear end corner portion and is formed in such a manner as to wrap around and extend toward the front of the vehicle (or a vehicle body front end corner portion formed in such a manner as to wrap around toward the front of the vehicle), it is necessary to arrange the reflector relatively far apart from a translucent cover extending along the surface of the vehicle body to prevent interference with the translucent cover. Accordingly, there is a problem that the size of the lamp is rather large.
On the contrary, as shown in FIG. 7, by forming a reflector 102 so as to wrap around along a translucent cover 104 and arranging a plurality of sets of LED light sources 106 and Fresnel lenses 108 on a curve following the wrap-around shape, it is possible to make the lamp thin. However, in such a lamp, the light by the reflector 102 from the respective LED light sources 106 is reflected in a direction normal to the curve, as indicated by arrows in FIG. 7. Therefore, there is a problem that it is not possible to obtain sufficient light radiated to the front of the lamp.
Taking the foregoing situation into consideration, it is an object of the present invention to provide a vehicular lamp in which light is radiated by means of indirect illumination using a plurality of LED light sources and in which it is possible to make the lamp thin while a sufficient light output can be obtained to the front of the lamp, even in the case where the lamp is provided in a vehicle body wrap-around portion.
The present invention achieves the object mentioned above by providing an improved structure of a reflector.
That is, according to the present invention, a vehicular lamp is provided comprising: a plurality of LED light sources; a plurality of lenses for forming light from the respective LED light sources into respective parallel light fluxes; a reflector for reflecting the parallel light flux from each respective lens toward the front of the lamp; and a translucent cover provided on the front of the reflector, wherein the respective lenses are arranged so as to align the directions of the parallel light fluxes, the reflector is separated into sub-reflectors for every area of the reflector which the parallel light fluxes from the respective lenses strike, and the respective sub-reflectors are arranged in a stepped configuration stepping rearward from a front end position of the reflector toward a rear end position of the lamp.
The specific structure of the lens is not particularly limited so long as the lens can form the light from the LED light source into a parallel light flux. For example, it is possible to employ a single spherical lens, a combination lens, a Fresnel lens, or the like.
The specific direction of the parallel light fluxes is not particularly limited so long as the direction is in the direction of a line intersecting the longitudinal direction of the lamp. For example, it is possible to set it to an upward direction or a lateral direction by making it perpendicular to the longitudinal direction of the lamp.
The reflector may be structured such that a plurality of sub-reflectors are integrally formed, or may be structured such that the sub-reflectors are independently formed.
The specific structure of each of the sub-reflectors, such as the shape, size or the like, is not particularly limited as long as the sub-reflectors reflect the parallel light fluxes from each of the lenses toward the front of the lamp.
The direction perpendicular to the longitudinal direction of the lamp mentioned above may be the lateral direction of the lamp, the vertical direction of the lamp, or the diagonal direction of the lamp.
The vehicular lamp according to the present invention is constructed such that the plurality of lenses which form the light from a plurality of LED light sources into parallel light fluxes are arranged so as to align the radiating directions of the parallel light fluxes. Further, the reflector for reflecting the parallel light fluxes from the respective lenses toward the front of the lamp is separated into sub-reflectors for every area of the reflector which the parallel light fluxes from the respective lenses strike, and the respective sub-reflectors are arranged in a stepped configuration extending from the front end of the lamp toward the rear end of the lamp. With these arrangements, the following effects can be obtained.
Because the reflector is constituted by a plurality of sub-reflectors arranged in a stepped configuration, even in the case where the translucent cover is formed so as to wrap around to the rear of the lamp with respect to the direction perpendicular to the longitudinal direction of the lamp, it is possible to form the reflector so as to wrap around along the translucent cover while the reflected light from the respective sub-reflectors is radiated toward the front of the lamp.
Therefore, in the vehicular lamp of the invention structured such that light is radiated by indirect illumination using a plurality of LED light sources, it is possible to achieve a thin structure of the lamp as well as sufficient radiated light to the front of the lamp, even in the case where the lamp is designed to be mounted in a vehicle body wrap-around portion.
In the structure mentioned above, the lengths in the radiating direction of the parallel light fluxes of each of the sub-reflectors may be made the same, or the lengths may be set to different values from each other corresponding to the shape of the lamp or the like. In the case of employing the latter structure, if the sub-reflectors are formed such that the tilt angle relative to the front of the lamp, that is, with respect to the vertical direction of lamp, becomes larger as the length of the sub-reflectors in the direction of the parallel light fluxes radiating direction becomes shorter, it is possible to make all the parallel light fluxes from the respective lenses strike the reflecting surface of each of the sub-reflectors without loss.
The reflecting surface of each of the sub-reflectors may be constituted by a single curved surface, or the surface may be constituted by a plurality of reflective elements. In the latter case, when the reflecting surface of each of the sub-reflectors is divided into a plurality of segments, and a reflective element and a step portion are formed in each of the segments such that the reflecting surface is formed in a stepped configuration, it is possible to effectively radiate the light to the front of the lamp.
Moreover, if each of the reflective elements is constituted by a curved surface which reflects the parallel light flux from the lens in a diffused manner in vertical direction and lateral directions, it is possible to obtain the required lamp light distribution performance even if the translucent cover is formed in a plain configuration. (By xe2x80x9cplain configurationxe2x80x9d is meant that the translucent cover has no lens elements to diffuse the light passing therethrough.)
Alternatively, each of the reflective elements can be constituted by a flat plane so as to reflect the parallel light flux from the lens toward the front of the lamp while maintaining the light flux parallel, in which case diffusion lens elements are formed in the translucent cover or the like, thereby diffusing the light in both the vertical and lateral direction. In another alternative configuration, the reflective elements can each be constituted by a curved surface having curvature only in one direction so as to reflect the parallel light fluxes from the lens toward the front of the lamp only in one direction in a diffused manner, in which case diffusion lens elements are formed in the translucent cover or the like to diffuse the light in the direction perpendicular to the one direction mentioned above.